A mixed 2x2x400 metres relay and a mixed shuttle hurdles relay will now feature in the Japanese city, meaning in total the event will now have three men’s events, three women’s events and three mixed events, making it more evenly balanced.

The 2x2x400m event will replace the 4x800m which the IAAF claim had "limited appeal" at previous Championships.

The shuttle hurdles relay will feature two men and two women on each team, with the first man running 110m hurdles in one direction, before handing over to the first woman who will then run back down the straight in the other direction.

To make up for the extra distance, the women will run an extra 10m at the end of their leg.

Former Olympic and world 100m hurdles champion Sally Pearson is one athlete to have given her support to the proposal. 

"I’m excited that the hurdles can be part of a relay," the Australian said.

"I always enjoy participating in the traditional relays and now that my own event can be incorporated into a team event, it makes the World Relays even more enticing."

The 32-year-old Pearson added, however, that she is not sure yet if she will compete at the event on May 11 and 12 as she continues her recovery from an Achilles injury that ruled her out of last year's Commonwealth Games.

"It all depends on what the body decides," she said.

"If I can make the IAAF World Relays a part of my pre-World Championships schedule, I’ll be one excited athlete – especially now that the hurdles is featuring."

Another athlete to have backed the concept is European 110m hurdles champion Pascal Martinot-Lagarde.

"I’ve always been a little envious because I could never take part in a sprint relay," he said. 

"But now that the IAAF is introducing the shuttle hurdles relay, the world is in for a great show."

The mixed 2x2x400m event meanwhile, will be an endurance relay requiring both members of the team to run two 400m legs.

As with the mixed 4x400m each team can choose whether to start with a man or woman, with the athletes then taking it in turns to run their legs.

"I like the idea of this relay because it’s comparable to the 800m," said European 800m champion Adam Kszczot.

"I love it actually."

IAAF President Sebastian Coe revealed he is excited to see how the events unfold.

"The IAAF World Relays is our youngest World Athletics Series event and it was designed to be fun for our athletes and fans so it's the perfect place to try new formats," he said.

"I’ve been championing innovation in our sport since I took the reins so it’s great to see the addition of a dynamic relay that will showcase our sprint hurdlers and I’ll be fascinated to see how the mixed 2x2x400m relay unfolds as a new endurance event that has never been tried before in athletics.

"I’m sure that both will contribute to the youthful, energetic atmosphere of the event, which we’re confident will be a resounding success in our new host city Yokohama in May."

The IAAF world Relay Championships was first held in 2014 and has always previously taken place in the Bahamas.

This year, though, it will go ahead in Japan in anticipation of the 2020 Olympic Games, which will be held in Tokyo the following year.